Tiger Airways (J7X.SG) is +1.1% at $1.82, in average volume of 939,000 shares so far, as the airline’s solid December operating data fail to generate much excitement.

The carrier reported it flew 555,000 passengers in December, +22% on-year, +19.6% on-month, at an average load factor of 91%, +1 percentage point on-year.

Credit Suisse says Tiger “continues to enjoy strong traffic growth” with an “impressive” load factor, but “despite the strong traffic numbers, we reiterate our Underperform rating on the stock, as we see limited potential upside.

Moreover, valuations remain expensive.” At 14.2x CY2011E P/E, says Tiger is the most expensive LCC under Credit Suisse’s coverage.

Credit Suisse has a S$1.90 target price. The house adds, “going forward, we expect a seasonally stronger 4Q FY11, driven by the Chinese New Year festive period and the Australian summer.” Orderbook suggest $1.83 may cap today, then YTD high at $1.86.